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Active supercontraction in rolling‐up muscles of Glomeris marginata (myriapoda, diplopoda)
Author(s) -
Carnevali Maria Daniela Candia,
Valvassori Roberto
Publication year - 1982
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.1051720107
Subject(s) - sarcomere , anatomy , biology , actin , contraction (grammar) , muscle contraction , myosin , biophysics , myocyte , microbiology and biotechnology , endocrinology
The lateroventral muscles of Glomeris marginata keep the animal rolled up and are able to develop and maintain great tension. Their fibers are not equipped with a particularly strong contractile apparatus but can super‐contract. The sarcomere shortens its resting length by up 60% and in a typical supercontraction the thick filaments pass through the Z‐line into adjacent sarcomeres. The Z‐line structure changes according to the contraction state: It passes from a homogeneous, dense zig‐zag line in decontracted fibers to a rarified, vaguely outlined Z‐band in supercontracted fibers, in which it is possible to see actin and myosin filaments. The Z‐line is thus involved in an active expanding process and is functionally very different from the fragmented and discontinuous Z‐line of “classical” supercontracting muscles. The different meaning of the two cases of supercontraction is discussed.